Doctoral theses of the School of Engineering are available in the open access repository maintained by Aalto, Aaltodoc.
Public defence in Energy Technology, M.Sc. Mika Lehmusto
Public defence from the Aalto University School of Engineering, Energy and Mechanical Engineering department.
When
–
Where
Lecture Hall 216, Otakaari 4, K1 Building, 02150 Espoo
Event language(s)
English
Title of the thesis: Towards net-zero shipping: Sustainable energy and power in future marine vessels
Thesis defender: Mika Lehmusto
Opponent: Prof. Pertti Kauranen, LUT, Finland
Custos: Prof. Annukka Santasalo-Aarnio,Aalto University School of Engineering
Towards net-zero shipping: Sustainable energy and power in future marine vessels
International maritime transport is at a turning point as it strives to achieve the International Maritime Organization’s (IMO) target of net-zero greenhouse gas emissions by 2050. Achieving this goal requires a comprehensive transformation in energy production technologies, power transmission systems, and circular economy practices.
As the maritime sector moves toward more sustainable propulsion solutions, choices related to energy production, storage, distribution, energy conversion, and engine technologies will determine both environmental performance and long-term economic viability over a vessel’s lifecycle. This dissertation systematically analyzes and compares alternative propulsion and power transmission solutions, and evaluates their environmental and economic impacts as well as their role in guiding ship design toward a low-emission and commercially sustainable future.
The research integrates three complementary domains: sustainable fuel options for icebreakers, experimental performance analysis of first- and second-life batteries, and lifecycle cost modeling of onboard energy storage systems for maritime vessels. Methodologically, the study combines laboratory-scale aging experiments, lifecycle and total cost of ownership modeling, and vessel-level techno-economic simulations based on operational measurement data from the Polaris icebreaker and the fully electric ferry Ellen. Comparative analyses cover fossil, synthetic, and small modular reactor-based energy options, while a circular economy framework assesses the reuse potential and residual value of propulsion batteries under different market and cost scenarios.
The dissertation provides methods and insights to support designers in the early conceptual design phase—when critical decisions are made regarding a vessel’s energy system and its future emissions. It demonstrates that designing a technically, economically, and environmentally sustainable vessel concept across its entire lifecycle is a multifaceted challenge that requires technical expertise, systems-level thinking, and the ability to make pragmatic choices. This research offers timely knowledge on how ships can meet future IMO emission targets while maintaining their commercial competitiveness.
Keywords: Marine decarbonisation, circular economy, second-life batteries, alternative marine fuels, icebreaker
Thesis available for public display 7 days prior to the defence at .
Contact information: mika.lehmusto@aalto.fi
Doctoral theses of the School of Engineering
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